Abstract:The atmospheric boundary layer is a passage between the atmosphere and the land surface, through the atmospheric momentum, energy and substances are transported upwards and downwards in two layers on earth surface.In the lower atmospheric planetary boundary layer turbulent transport is important connection for substance and energy exchange between the atmosphere and the earth surface, currently it is one focus of earth system science. By using open-path eddy covariance system and micro-climate instruments, the net radiation, sensitive heat flux, latent heat flux, soil heat flux, air temperature, soil temperature, and precipitation were conducted in Mao bamboo forest ecosystem of subtropical in China since 2011. But the energy flux and analysis of Mao bamboo forest ecosystem reported in the literature at home and abroad is very few, in subtropical regions to establish long-term continuous observation of the flux tower, enhancing the research is highly requirement. The diurnal and monthly variation of energy balance as well as the distribution pattern of each component were analyzed, and energy closure and Bowen ratio also were calculated. As an important index to evaluate the reliability of eddy covariance measurements, energy balance analysis has been widely accepted by the community. Using two methods of OLR(Ordinary least spuares) and EBR(Energy balance ratio), energy imbalance characteristics of the Mao bamboo forest ecosystem were systematically analyzed compared in the paper. The results showed that: the yearly net radiation of the Mao bamboo forest ecosystem was 2628.00 MJ/m2, and the sensitive flux heat, latent heat flux, and soil heat flux were 576.80 MJ/m2, 1666.77 MJ/m2, and -7.52 MJ/m2, respectively. The results suggest that soil of Mao bamboo forest was a heat source. The energy balance components had obvious seasonal pattern, diurnal variations of energy balance components existed on expected single peaks. The sensible and latent heat fluxes almost have 22.0% and 63.4% of the net radiation, respectively, indicating that latent heat flux was the main form of energy loss in this forest ecosystem. Monthly variation of the Bowen ratio is slight, and fluctuated from 0.07 to 1.77, the yearly enrgy balance closure of the Mao bamboo forest ecosystem was 0.85, and the mean monthly averge was 0.84, yet energy imclosure of 15% still existed for the energy balance of Mao bamboo forest ecosystem.
